Mining equipment often requires power from an external power source. The mining equipment may be tethered to the external power source by portable power cables, which may be referred to as trailing cables. The trailing cables are used to supply power to various types of mining equipment such as, for example, pumps, drills, shovels, and other mining machines.
Trailing cables and mining equipment attached thereto often pose elevated safety risks. Mine machine operators may be exposed to electrical hazards caused by trailing cable damage, a line-to-ground fault existing in the mining machine, or a broken or damaged ground conductor. To ensure proper grounding of the mining machine, a ground check monitor can be used with the trailing cables. In the event of trailing cable damage as detected by the ground check monitor, mining equipment can be de-energized to protect the mining machine operator.
Conventional ground check monitors suffer from one or more problems. For example, conventional ground check monitors often use a Zener diode terminated ground check circuit. Alternating current (AC) effects can be induced on a Zener diode terminated ground check circuit. The induced AC effects on the Zener diode can create a significant error on a measured ground resistance, thus making it virtually impossible to measure ground resistance to a required accuracy.